Articles
Mechanics Based Design of Structures and Machines (15397742)
This study investigates dynamic behavior of railway bridges subjected to lateral impact load induced by over-height vehicle while a train passes over the bridge. The lateral displacement at the bottom of the bridge girder subjected to impact load is first compared with the specified value considering the bridge elastic and plastic behavior using finite element model (FEM). Then, in the railway bridge sector, different sensitivity analyses are performed on the parameters of lateral displacement, vertical and lateral bridge deck acceleration, sleeper lateral displacement and vertical and lateral rail acceleration on the same and opposite sides of the impact load at different impact loads induced by changes in the impact velocity. In the vehicle sector, vertical and lateral forces of wheel-rail contact and lateral acceleration of the train bogie are obtained at the impact load of 8,700 kN considering the bridge plastic behavior. Finally, the results obtained from dynamic analysis of train-track-bridge interaction revealed train running safety indices exceed the allowed values specified by China Railway Regulations as the impact load exceeds 66 MN in terms of derailment factor and 4 MN in terms of offload factor. © 2025 Taylor & Francis Group, LLC.
Iranian Journal Of Science And Technology, Transactions Of Civil Engineering (22286160)49pp. 3631-3645
The purpose of this study is to look into ways of increasing trains speed in a railway network. To this end, an elastic and resilient layer under ballast layer was used as a retrofitting process of existing short-span reinforced concrete railway bridges which are commonly used bridges in railway networks. A three-dimensional finite element model incorporating the bridge, train, and track was developed. The model includes the train-track interaction, using an elastic and resilient layer under ballast layer in two types of bridge bearing (rigid and elastic bearing) for bridge span lengths of 2, 4, 6, and 8 m. Field test results were employed to authenticate the model, focusing on the impact of escalating train velocity in diverse ballast layer and bridge bearing scenarios. The utilization of resilient layer under ballast layer was shown to reduce the maximum values of the bridge deck’s acceleration and vertical displacement up to 30% and 20%, respectively. Furthermore, it was discovered that the train wagon vehicle body’s vertical acceleration increased at 140 km/h and decreased at 200 km/h. The method proposed here not only improves the operation condition of existing railway bridges, but also save environment from a vast amount of end-of-life waste tires. © The Author(s), under exclusive licence to Shiraz University 2024.
